Liquid spray device

ABSTRACT

There is disclosed a dishwasher having an improved bearing and seal construction for the spray arm. The spray arm is mounted for limited vertical movement with respect to the outlet conduit of a pump. When pump pressure is applied to the spray arm, the spray arm is lifted out of load supporting engagement with the conduit and engages a seal which reduces liquid leakage around the spray arm. When pump pressure is interrupted the spray arm returns to the supported position, allowing the spray arm to drain. The spray arm is removably mounted onto the conduit to allow for servicing of the dishwasher.

[ Dec. 4, 1973 United States Patent 1 Baker 1 LIQUID SPRAY DEVICE 3,077,200 2/l963 Guth 239/251 [75] Inventor: Philip D. Baker, Jefi'ersonville, Ind.

[73] Assignee: General Electric Company,

I Primary Examiner-Lloyd King Attorney-George C. Atwell et a].

Louisville, Ky.

ABSTRACT There is disclosed a dishwasher having an improved bearing and seal construction for the spray arm. The spray arm is mounted for limited vertical movement with respect to the outlet conduit of a pump. When pump pressure is applied to the spray arm, the spray [52] US. 239/251, 239/261 [51] Int. B05b 3/06 58 Field of 239/251, 259, 260, am is lifted out of load Supporting engagement wlth 239/26l, 264, 285/281, 90; 34 277/178 the conduit and engages a seal which reduces liquid leakage around the spray arm. When pump pressure is interrupted the spray arm returns to the supported po- [56] References Cited UNITED STATES PATENTS sition, allowing the spray arm to drain. The spray arm is removably mounted onto the conduit to allow for servicing of the dishwasher.

239/251 12 Claims, 6 Drawing Figures All PATENTEU M975 sum 1 BF '2 FIG! PATENTEU SHEET 2 OF 2 FIG. 3

FIG.

FIG.

BACKGROUND OF THE INVENTION This invention relates to rotatable spray devices and particularly to a reactive spray device having means for sealing a rotary spray arm on a stationary tubular pedestal. The device of this invention is particularly adaptable for use in an automatic dishwasher such as disclosed in U.S. Pat. No. 3,451,400 which is assigned to the assignee hereof.

In conventional dishwashers, a fixed pump outlet conduit or tubular pedestal extends into the washing chamber of a dishwashing machine and has a rotatable spray arm mounted thereon for distributing a washing liquid spray over tableware within the washing chamber. This invention comprises an improved bearing and seal arrangement allowing rotation of the spray arm with respect to the pedestal and substantially sealing the junction between the rim of the tubular pedestal and the spray am.

The bearing construction suggested in the prior art for dishwashing machines contemplates relatively massive bearing structures, as exemplified by U.S. Pat. Nos. 3,009,470; 3,370,869; and 3,599,872. Since cost is roughly proportional to weight in mass produced items, it will be appreciated by those skilled in the art that the cost of prior art bearing structures is appreciable. The device of this invention eliminates the requirement for relatively massive bearing structures and accordingly allows the construction of a high quality, inexpensive spray arm support.

As spelled out in some detail in U.S. Pat. No. 3,599,872, the seal between the tubular pedestal and the spray arm is desirably leak free although a small amount of leakage can be tolerated. It will be apparent to those skilled in the art that the mechanical efficiency of the dishwasher improves as the leakage around the spray arm is decreased. The device of this invention substantially reduces leakage between the spray arm and the tubular pedestal and accordingly enhances efficiency of the dishwasher.

Of interest with respect to this invention are the disclosures in U.S. Pat. Nos. 1,776,714; 1,784,314 and 2,560,833. The disclosure of these references comprises a relatively stationary tubular pedestal and a spray arm mounted for rotation and for limited vertical movement between sealing and non-sealing positions.

The bearing and seal construction in prior art dishwashing machines has functioned satisfactorily but suffers from the cost of making relatively massive structures. The bearing and seal arrangements exemplified by U.S. Pat. No. 2,560,833 are not susceptible for bodily incorporation in a dishwasher since dishwashers must be disassembled in order to service the same. Typical service problems encountered with spray arms are clogging of the spray arm orifices as with corn kernels or the like, replacing and/or cleaning of seals which minimize liquid leakage and replacement of the gasket that seals the tubular pedestal to the bottomof the washing chamber. Bodily incorporation of bearing-seal constructions of the type shown in U.S. Pat. No. 2,560,833 would frustrate attempts at servicing the machine and accordingly would not prove satisfactory. The device of this invention allows disassemblage of the spray arm and spray arm support for servicing while providing an inexpensive, high quality bearing and seal.

SUMMARY OF THE INVENTION In summary, the dishwashing machine of this invention comprises a washing chamber; means for delivering washing liquid to the chamber including a source of pressurized washing liquid, a spray arm, conduit means for delivering washing liquid from the source to the spray arm; means removably mounting the spray arm on the conduit means for vertical movement between a first position supporting the arm on the conduit and a second elevated position out of supported relation therewith and means providing a bearing operative in the second position for rotatably mounting the spray arm about a generally vertical axis; the removable mounting means comprising a member, mounted within the spray arm, removably connected to the conduit for captivating the spray arm between the first and second positions thereof and a closure removably connected to the spray arm providing access to the removable member; means for rotating the spray arm; and means responsive to pressurized washing liquid in the spray arm for raising the spray arm from the first position to the second position.

A particular feature of the invention is the provision of means, in combination with the structure heretofore described, permitting automatic drainage of residual liquid from the spray arm as an incident of the spray arm returning to its first position when the flow of pressurized liquid therethrough is curtailed.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a broken front elevational view of a typical automatic dishwasher;

FIG. 2 is a partial plan view of the bottom of the washing chamber of the machine illustrated in FIG. 1;

FIG. 3 is an enlarged vertical cross sectional view of the junction between the spray arm and the tubular support therefor of the machine illustrated in FIG. 1;

FIG. 4 is a vertical cross sectional view of the structure of FIG. 3, taken substantially along line 44 thereof as viewed in the direction indicated by the arrows;

FIG. 5 is an enlarged cross sectional view of the junction between the spray arm and the support therefor illustrating the spray arm in the operating or sealed position; and

FIG. 6 is a view similar to FIG. 3 illustrating a slightly different type of spray arm.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, there is illustrated an automatic dishwashing machine 10 including a cabinet 12 defining an internal washing chamber 14. Access to the chamber 14 is provided by a door 16 hinged along its lower edge in a conventional manner. Upper and lower dish supporting racks 18, 20 are slidably mounted on the cabinet 12 and may be manually withdrawn through the access opening afforded by the door 16 to facilitate loading and unloading of tableware.

The bottom of the washing chamber 14 is defined by a sloping wall 22 providing a drain opening 24. The bottom wall 22 separates the washing chamber 14 from a pump-motor compartment 26 that houses a pump 28 and an electric motor 30. The pump 28 acts to recirculate washing liquid in the chamber 14 or to drain washing liquid out of the dishwasher 10. The motor 30 drives the pump 28 and is controlled by a typical timer (not shown) which is normally located on the door 16. Conventionally, the timer also controls operation of a suitable electrical heating element 31 (FIG. 2) to control drying.

Extending upwardly from the pump outlet housing is conduit means 32 which passes through a humped segment 34 of the bottom chamber wall 22. The conduit means 32 typically comprises a flexible hose 36 interconnecting the pump housing outlet and a rigid stationary sleeve 38 which projects into the washing chamber 14. The sleeve 38 is sealed against the humped bottom wall segment 34 by a rubber gasket 40. The sleeve 38 conveniently includes threads 42 for cooperating with similar threads 44 on the underside of the humped bottom wall segment 34 for compressing the gasket 40. As will be more fully pointed out hereinafter, the sleeve 38 includes a plurality of ribs 46 extending vertically along the exterior of the upper section thereof.

A spray arm 48 is mounted by means 50 adjacent the top of the sleeve 38 for rotation about a generally vertical axis and for limited axial movement as will become more fully apparent hereinafter. The spray arm 48 is typically made of metal or plastic and comprises a lower imperforate section 52 and a perforate upper section 54 which are crimped together as illustrated best in FIG. 4. As shown in FIG. 2, the spray arm 48 is of the symmetrical type having a plurality of upwardly directed spray openings 56 and a pair of symmetrically disposed reaction nozzles 58. As will be apparent to those skilled in the art, delivery of washing liquid from the pump 28 causes liquid emission through the openings 56 and the nozzles 58. Liquid emitting from the nozzles 58 causes the spray arm 48 to rotate about a vertical axis while washing liquid emitting from the openings 56 is projected onto tableware located in the racks 18, 20. Since the spray arm 48 is of the symmetrical variety, it will be apparent that there is no substantial lateral loading of the arm 48 during spraying.

Projecting upwardly from the center of the spray arm 48 is an extensible spray tower 60 of the type illustrated in U.S. Pat. No. 3,077,200. The spray tower 60 comprises an outer conduit 62 threaded into a connection 64 which is sealably connected to the upper spray arm section 54. The spray tower 60 also comprises an inner conduit 66 which is illustrated in FIGS. 3 and 4 in the non-operating position. Upon delivery of pressurized washing liquid to the spray arm 48, the inner conduit 66 is extended upwardly to discharge washing liquid in the chamber 14 in accordance with the disclosure of U.S. Pat. No. 3,077,200, to which reference is made for more complete understanding of the spray tower 60. Suitable means (not shown) are provided adjacent the upper end of the outer conduit 62 to limit the upward movement of the inner conduit 66 and to provide a seal between the conduits 62, 66,

As mentioned previously, an important feature of this invention resides in the bearing and seal arrangement for mounting the spray arm 48. As shown best in FIGS. 3-5, the lower spray arm section 52 provides an opening to receive pressurized washing liquid from the pump 28. The inner edge 68 of the arm section 52 is reverted to provide a lip of substantial strength. In the non-operating position illustrated in FIGS. 3 and 4, the spray arm 48 and spray tower 60 are supported by the ribs 46. It will be apparent that, in the non-operating position, there is provided a generally unobstructed flow path from the interior of the spray arm 48 to the interior of the washing chamber 14. To minimize any obstruction in the flow path, a minimum number of ribs 46 are selected. When pressurized liquid flow through the spray arm 48 and the tower is curtailed the residual liquid will flow out through openings such as 56 of the spray arm. Thereafter, liquid in the spray arm drains out between the ribs 46. The washing liquid within the spray arm 48 and the tower 60 drains into the washing chamber 14 between each step of the dishwashing cycle. This is advantageous since contaminant carry-over of residual liquid between washing and rinsing steps is substantially reduced. This is particularly desirable immediately prior to last rinsing step so that the last rinse of tableware in the racks 18, 20 is conducted with water that is as clean as possible.

The mounting means 50 is removably connected to the upper end of the sleeve 38 as by suitable threads or camming lugs and includes a flange 70 overlying the inner edge 68 of the lower spray arm section 52. A low friction bearing and sealing member 72 is positioned on the underside of the flange 70 for engagement with the inner spray arm edge 68. As will be apparent to those skilled in the art, the bearing and sealing member 72 may be of any suitable material, such as tetrafluoroethylene or the like. The sealing and bearing member 72 is preferably retained against the underside of the flange 70 as by the provision of a plurality of spacers 74. The spacers 74 desirably do not substantially obstruct the flow path across the inner edge 68. To this end, a minimum number of spacers 74 is used. In one prototype of the invention, three equally positioned spacers 74 were employed. The spacers 74 may be integral with the bearing and sealing member 72 or separate therefrom.

As pressurized washing liquid is delivered into the spray arm 48, an imbalance of forces acting on the spray arm 48 is created. As will be appreciated by those skilled in the art, the upwardly directed force acting on the spray arm 48 is the product of the pressure in the spray arm 48 and the upwardly directed surface area thereof. Similarly, the downwardly directed force on the spray arm 48 is the product of the pressure in the spray arm 48 and the downwardly directed surface area thereof. In order for the spray arm 48 and the spray tower 60 to function as spray devices, the area of the spray openings must necessarily be less than the area of the throat 76. Accordingly, the downwardly directed area on the spray arm 48 is less than the upwardly directed surface area thereof which creates a net upward force on the spray arm 48. Since the spray arm 48 is free to move vertically within the limits defined by the ribs 48 and the flange 70, the spray arm 48 is elevated until the inner edge 68 engages the sealing and bearing member 72. Generally contemporaneously with upward movement of the spray arm 48, the inner conduit 66 of the spray tower 60 is elevated.

As washing liquid passes through the reaction nozzles 58, the spray arm 48 rotates about a generally vertical axis. Since the openings 56, S8 in the spray arm 48 are symmetrical, no substantial lateral force is imposed on the spray arm 48 thereby eliminating the requirement for a relatively massive bearing to constrain the arm 48 against lateral movement. As the spray arm 48 is elevated from the position of FIGS. 3 and 4 to the position of FIG. 5, the inner edge 68 bears against the member 72 thereby providing a seal for restricting or reducing liquid leakage at the junction of the spray arm 48 and its tubular pedestal and providing a bearing facilitating rotation of the spray arm 48.

As mentioned previously, it is highly desirable for the spray arm 48 to be removable to facilitate servicing. Typical servicing problems which occur in the dish washer l0 downstream from the pump housing outlet are the deterioration (either by aging or by chemical reaction with caustic washing products) of the gasket 40, wear of the bearing and sealing member 72 and clogging of the openings 56, 58 in the spray arm 48. It will be readily apparent that the device of this invention may be disassembled quickly and with a minimum of required tools. The spray tower 60 may be unscrewed from the connection 64 leaving an opening in the upper section 54 of the spray arm 48. This opening provides access to the mounting means 50 which preferably includes a handle 78 for unscrewing the mounting means 50 from the sleeve 38. As shown in FIGS. 3 and 4, the handle 78 affords a support for the inner conduit 66 in its non-operating position. Unscrewing the mounting means 50 releases the spray arm 48. For purposes of convenience, the maximum diameter of the mounting means 50 is less than the inside diameter of the connection 64 thereby allowing ready manufacture of the spray arm 48 as well as easy removal thereof. When the spray arm 48 is removed from the sleeve 38, the sleeve 38 may be unscrewed from the threads 44. It will accordingly be seen that the device of this invention is readily disassembled and provides easy access to the gasket 40 and the seal 72 which necessarily suffer the greatest amount of wear and deterioration.

Referring to FIG. 6, there is illustrated a substantially identical seal bearing'structure in a dishwasher that does not include the spray tower. For purposes of brevity, analogous reference characters are used to designate identical components with only the difi'erences between the embodiments being specifically discussed. In lieu of the spray tower 60, there is provided a cap 180 threadably received by the connection 164. It will be apparent that the cap 180, like the spray tower 60, acts as a removable closure providing access to the mounting means 150.

I claim:

1. A dishwashing machine comprising a washing chamber;

means for delivering washing liquid to the chamber including a source of pressurized washing liquid, a spray arm, conduit means for delivering washing liquid from the source to the spray arm; means removably mounting the spray arm on the conduit means for vertical movement between a first position supporting the arm on the conduit means and a second elevated position out of supported relation therewith and means providing a bearing operative in the second position for rotatably mounting the spray arm about a generally vertical axis;

the removable mounting means comprising a member, mounted within the spray arm, removably connected to the conduit for captivating the spray arm between the first and second positions thereof and a closure removably connected to the spray arm providing access to the removable member;

means for rotating the spray arm; and I means responsive to pressurized washing liquid in the spray arm for raising the arm from the first position to the second position.

2. The dishwashing machine of claim 1 further comprising means for draining residual liquid from the spray arm as an incident of the spray arm returning from the second position to the first position.

3. The dishwashing machine of claim 1 further comprising means on the conduit means operative in the second position only for sealably engaging the spray arm and reducing liquid leakage between the spray arm and the conduit means.

4. The dishwashing machine of claim 2 wherein the closure comprises an extensible spray tower carried by the spray am.

5. The dishwashing machine of claim 2 wherein the spray arm rotating means comprises symetrically disposed reaction nozzles in the spray arm.

6. The dishwashing machine of claim 2 wherein the closure is a cap.

7. The dishwashing machine of claim 2 wherein the spray arm provides an opening, defined by an edge, surrounding the conduit; the member provides a downwardly facing lip overlapping the edge; and the sealing means and the bearing means comprising a common low-friction member between the lip and the edge.

8. The dishwashing machine of claim 7 further comprising means for holding the low-friction member against the lip.

9. The dishwashing machine of claim 3 wherein the upper end of the conduit provides a plurality of spaced upwardly facing shoulder means for receiving the spray arm edge in load supported relation.

10. The dishwasher of claim 7 wherein the conduit means comprises a sleeve projecting through the bottom of the washing chamber, means for sealing the sleeve thereto and means removably connecting the sleeve to the bottom of the washing chamber.

11. The dishwashing machine of claim 4 wherein the member provides a handle extending toward the spray tower; and

the spray tower comprises an outer conduit removably connected to the spray arm and an inner conduit for axial movement within the outer conduit, the inner conduit being in supported relation to the handle in the unextended position of the spray tower.

12. A dishwashing machine comprising a washing chamber;

means for delivering washing liquid to the chamber including a source of pressurized washing liquid, a spray arm, and a conduit for delivering washing liquid from the source to the spray arm;

means removably mounting the spray arm on the conduit for vertical movement between a first position supporting the arm on the conduit and a second elevated position out of supported relation therewith and means providing a bearing operative in the second position for rotatably mounting the spray arm about a generally vertical axis;

the removable mounting means comprising a member for captivating the spray arm between the first and second positions thereof and means removably connecting the member to the conduit;

means for rotating the spray arm; and

means responsive to pressurized washing liquid in the spray arm for raising the arm from the first position to the second position.

o f UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION patent 3,776,465 D d December 4, 1973 Inventor(s) Philip D. Baker It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Claim 9, line 27, "Claim 3" should read Claim 7 sighed and sealed this 2nd day of July 1974.

(SEAL) Attest: I

EDWARD M. FLETCHER,JR. C.MARSHALL DANN Attesting Officer Commissioner of Patents FORM PO-1Q5O (10-69) USCOMM-DC 60376-F'69 U45. GOVERNMENT PRINTINSS OFFICE: l99 Ov366334 

1. A dishwashing machine comprising a washing chamber; means for delivering washing liquid to the chamber including a source of pressurized washing liquid, a spray arm, conduit means for delivering washing liquid from the source to the spray arm; means removably mounting the spray arm on the conduit means for vertical movement between a first position supporting the arm on the conduit means and a second elevated position out of supported relation therewith and means providing a bearing operative in the second position for rotatably mounting the spray arm about a generally vertical axis; the removable mounting means comprising a member, mounted within the spray arm, removably connected to the conduit for captivating the spray arm between the first and second positions thereof and a closure removably connected to the spray arm providing access to the removable member; means for rotating the spray arm; and means responsive to pressurized washing liquid in the spray arm for raising the arm from the first position to the second position.
 2. The dishwashing machine of claim 1 further comprising means for draining residual liquid from the spray arm as an incident of the spray arm returning from the second position to the first position.
 3. The dishwashing machine of claim 1 further comprising means on the conduit means operative in the second position only for sealably engaging the spray arm and reducing liquid leakage between the spray arm and the conduit means.
 4. The dishwashing machine of claim 2 wherein the closure comprises an extensible spray tower carried by the spray arm.
 5. The dishwashing machine of claim 2 wherein the spray arm rotating means comprises symetrically disposed reaction nozzles in the spray arm.
 6. The dishwashing machine of claim 2 wherein the closure is a cap.
 7. The dishwashing machine of claim 2 wherein the spray arm provides an opening, defined by an edge, surrounding the conduit; the member provides a downwardly facing lip overlapping the edge; and the sealing means and the bearing means comprising a common low-friction member between the lip and the edge.
 8. The dishwashing machine of claim 7 further comprising means for holding the low-friction member against the lip.
 9. The dishwashing machine of claim 3 wherein the upper end of the conduit provides a plurality of spaced upwardly facing shoulder means for receiving the spray arm edge in load supported relation.
 10. The dishwasher of claim 7 wherein the conduit means comprises a sleeve projecting through the bottom of the washing chamber, means for sealing the sleeve thereto and means removably connecting the sleeve to the bottom of the washing chamber.
 11. The dishwashing machine of claim 4 wherein the member provides a handle extending toward the spray tower; and the spray tower comprises an outer conduit removably connected to the spray arm and an inner conduit for axial movement within the outer conduit, the inner conduit being in supported relation to the handle in the unextended position of the spray tower.
 12. A dishwashing machine comprising a washing chamber; means for delivering washing liquid to the chamber including a source of pressurized washing liquid, a spray arm, and a conduit for delivering washing liquid from the source to the spray arm; means removably mounting the spray arm on the conduit for vertical movement between a first position supporting the arm on the conduit and a second elevated position out of supported relation therewith and means providing a bearing operative in the second position for rotatably mounting the spray arm about a generally vertical axis; the removable mounting means comprising a member for captivating the spray arm between the first and second positions thereof and means removably connecting the member to the conduit; means for rotating the spray arm; and means responsive to pressurized washing liquid in the spray arm for raising the arm from the first position to the second position. 